In recent years, the content distribution technology for distributing various content such as audio data, still images, and moving images has seen quick widespread use. The content distribution technology makes it possible for users to obtain desired contents via a network without having to carry transportable storage mediums.
FIG. 1 is a diagram showing one form of a general content distribution system.
The content distribution system shown in FIG. 1 comprises distribution server 1002 for distributing content, processing state management apparatus 1001 for managing processing states in distribution server 1002, and FTP server 1004 for storing various content, which are interconnected by network 1003.
Distribution server 1002 comprises distribution controller 1021, registration/deletion command controller 1022, state management controller 1023, content DB 1025 serving as a database for storing distributed content, and state DB 1024 serving as a database for storing registered/deleted states of content stored in contents DB 1025.
Distribution controller 1021 controls the distribution of content stored in content DB 1025.
Registration/deletion command controller 1022 controls the registration of content in contents DB 1025 and the deletion of content from content DB 1025 based on content registration/deletion requests sent from processing state management apparatus 1001.
State management controller 1023 stores the states of content registered/deleted by registration/deletion command controller 1022 into state DB 1024.
Processing state management apparatus 1001 comprises registration/deletion command controller 1011, state confirmation command controller 1012, state management controller 1013, and state DB 1014.
Registration/deletion command controller 1011 controls commands for sending requests to register/delete content to distribution server 1002.
State confirmation command controller 1012 controls commands for confirming the states of content stored in distribution server 1002 with distribution server 1002.
State management controller 1013 controls state DB 1014 which has stored the states of content acquired from distribution server 1002, according to the commands controlled by state confirmation command controller 1012.
FIG. 2 is a sequence diagram illustrative of a processing state management method in the content distribution system shown in FIG. 1.
When a content registration/deletion request generated by registration/deletion command controller 1011 is sent from processing state management apparatus 1001 through network 1003 to distribution server 1002 in step 91, registration/deletion command controller 1022 registers content, which is addressed by the content registration/deletion request, in content DB 1025 or deletes the content from content DB 1025, based on the content registration/deletion request that is sent. At this time, the content is acquired from FTP server 1004 or from a client terminal (not shown) which stores the content, and is registered in content DB 1025. The state of the registration/deletion of the content is stored in state DB 1024 by state management controller 1023.
While the content is being registered/deleted, in order for processing state management apparatus 1001 to confirm the progress of the registration/deletion of the content in distribution server 1002, a content registration/deletion state confirmation request for requesting the confirmation of the state of the registration/deletion of the content is generated by state confirmation command controller 1012 and sent via network 1003 to distribution server 1002 in step 92.
When the content registration/deletion state confirmation request is received by distribution server 1002, state management controller 1023 reads the state of the registration/deletion of the content from state DB 1024, and sends the read state of the registration/deletion of the content as a content registration/deletion state confirmation response via network 1003 to processing state management apparatus 1001 in step 93.
Thereafter, when registration/deletion command controller 1022 completes the registration of the content, which is addressed by the content registration/deletion request, into content DB 1025 or the deletion of the content from contents DB 1025, registration/deletion command controller 1022 sends a content registration/deletion completion response via network 1003 to processing state management apparatus 1001 in step 94. Even after the completion of a registration/deletion transaction in steps 91 through 94 is completed, processing state management apparatus 1001 sends a contents registration/deletion state confirmation request and distribution server 1002 sends a content registration/deletion state confirmation response in steps 95, 96.
FIG. 3 is a diagram showing an example of state information stored in state DB 1024 shown in FIG. 1.
As shown in FIG. 3, the state information stored in state DB 1024 represents contents registration/deletion states in distribution server 1002 based on content registration/deletion requests sent from processing state management apparatus 1001.
Before content is registered in distribution server 1002, state DB 1024 stores content state information representing “NO CONTENT”. When a content registration request is sent from processing state management apparatus 1001, the content state information stored in state DB 1024 is changed from “NO CONTENT” to “REGISTRATION IN PROGRESS”. When the registration of the content in content DB 1025 is completed in distribution server 1002, the content state information stored in state DB 1024 is changed from “REGISTRATION IN PROGRESS” to “CONTENT PRESENT”.
When a content deletion request is subsequently sent from processing state management apparatus 1001, the content state information stored in state DB 1024 is changed from “CONTENT PRESENT” to “DELETION IN PROGRESS”. When the deletion of the content from content DB 1025 is completed in distribution server 1002, the content state information stored in state DB 1024 is changed from “DELETION IN PROGRESS” to “NO CONTENT”.
A content registration/deletion state confirmation request from processing state management apparatus 1001 is made at constant time periods both while a transaction is being carried out and while a transaction is not being carried out until the registration/deletion of the content is completed. Each time a content registration/deletion state confirmation request is made, state management controller 1023 reads the state of the registration/deletion of the content from state DB 1024, and sends the read state of the registration/deletion of the content as a content registration/deletion state confirmation response via network 1003 to processing state management apparatus 1001. When the state of the registration/deletion of the content is sent as a content registration/deletion state confirmation response via network 1003 to processing state management apparatus 1001, the sent state of the registration/deletion of the content is stored in state DB 1014 by state management controller 1013.
In this manner, a content registration/deletion state confirmation request is sent from processing state management apparatus 1001 to distribution server 1002 irrespective of whether or not a transaction is being carried out. Each time a content registration/deletion state confirmation request is sent to distribution server 1002, distribution server 1002 makes an inquiry to state DB 1024 about the state of the content, and sends a content registration/deletion state confirmation response to processing state management apparatus 1001. As the quantity of content increases, the processing load on distribution server 1002 increases, tending to cause a delay due to congestion.
In order to avoid congestion due to the processing load, there has been proposed a technology for holding other processes while a certain instruction is being carried out (see, for example, JP No. 2005-92467A).
With general processing state management apparatus 1001 shown in FIG. 1, however, a content registration/deletion state confirmation request is sent to distribution server 1002, and each time a result is received, the state of the content needs to be registered in state DB 1014. Consequently, as the quantity of contents increases, the amount of data required to be held by processing state management apparatus 1001 is likely to increase.
According to another example, distribution server 1002 may not manage content states. However, this example needs to have a means by which processing state management apparatus 1001 can make an inquiry about the state of information to distribution server 1002.
The technology disclosed in JP No. 2005-92467A is problematic in that the total processing load is not reduced because the other processes that have been held will subsequently be carried out when the processing of the certain instruction is completed.